Air conditioning system



P 1940- 'H. L. STEINFELD 2, 96,687

AIR CONDITIONING SYSTEM Filed Jan. 16, 1937 2 Sheets-Sheet 1 Inventor J-EzmZdL. fiikz'rzf'eld 33/ M KM 'ftornqy April 1940. H. L. STEINFELD 7 AIR CONDITIONING SYSTEM Filed Jan. 16, 1957 2 Sheets-Sheet 2 IDS 1 W J O.

I02 95 C H v t J WINTER 75 8 SUMMER HaroZd L. Steznfeld Guam Patented Apr. 9, 1940 UNITED STATES PATENT OFFICE AIR CONDITIONING SYSTEM Harold L. Steinl'eld, East Orange, N. J., assignor to Minneapolis-Honeywell Regulator Company, Minneapolis, Minn., a corporation of Delaware It is an object of this invention to provide an air conditioning system for a building having a plurality of spaces wherein air conditioning means are provided for conditioning air and delivering conditioned air to all of the spaces, wherein means responsive to the condition of the air in certain of the spaces controls the condition of the conditioned air delivered to all of the spaces and wherein means responsive to the condition of the air in other of the spaces controls the volume of conditioned air delivered to these other of said spaces.

Another object of this invention is to provide an air conditioning system of the type outlined above along with the means for adjusting the condition responsive means in accordance with variations in the condition of the air outside of the building.

Another object of this invention is to provide an automatic summer-winter changeover for the condition responsive means which controls the volume of conditioned air delivered to the other of the spaces whereby the ,air conditioning system is adapted for year around operation.

Still another object of this invention is to pro-' vide an air conditioning system for a space having an air conditioning unit provided with heating means and cooling means for conditioning air delivered to the space along with means responsive to the space temperature for operating the heating means when the space temperature decreases and for operating the cooling means when the space temperature increases.

The specific structure and manner of operation for accomplishing the objects of this invention also form objects of this invention.

Other obiiects and advantages will become apparent to those skilled in the art upon reference to the .accompanying specification, claims and drawings.

For a more thorough understanding of this invention reference is made to the accompanying drawings in which:

Figure l diagrammatically discloses the preferred form of this invention as applied to a office spaces or the like.

Air for the spaces III, II and I2 is conditioned in an air conditioning unit l3 and the conditioned air is drawn from the unit l3 by means of a fan l4 and delivered through ducts l5 to the various spaces [0, ll

and I 2. Specifically, the air is delivered to the space Ill by an air inlet 16, to the space H by an air inlet I1 and to the space l2 by an air inlet I8. The fan It is suitably operated by an electric motor I9.

Return air is admitted to the air conditioning .be controlled by a manually operateddamper 25 and the volume of air delivered to the spaces H and I2 is controlled by automatically operated dampers 26 and 21 respectively. 1

The air conditioning unit [3 comprises an air moistening means in the form of a spray 29. The delivery of water to the spray 29 from a suitable water supply pipe 3| is controlled by a valve 30 which in turn is operated by a solenoid motor 32. The air conditioning unit I3 is also provided with a heating coil 33. The supply of heating medium, such as steam, to the coil 33 from a steam supply pipe 35 is controlled by a valve 34. The valve 34 is operated through a rack and pinion 36 by a modulating motor 31. The air conditioning unit I3 is also provided with a cooling coil which, for purposes of illustration is shown to be an evaporator 39. Refrigerant is drawn from the evaporator 39 by two compressors 40 and 4|. The compressors 40 and M are arranged in parallel with respect to each other and are operated by electric motors 42 and respectively. Refrigerant is discharged by the compressors 40 and I into a condenser 44. The refrigerant flows from the condenser 44 through an expansion valve 45 into the evaporator 39. Such a mechanical refrigerating apparatus is well known in the art and therefore a further description thereof is not considered necessary.

The valve 34 which controls the supply of heating fluid to the coil 33 and the compressors 40 and 4| which control the cooling effect of the cooling coil 39 are controlled by a thermostat generally designated at 41 responsive to the temperature of the space ID. The temperature setting of the thermostat. 41 is adjusted by an outdoor compensator generally designated at 48. The arrangement is such that upon a decrease in space temperature the steam valve 34 is modulated to increase the supply of heating fluid to the heating coil 33 and upon an increase in space temperature the compressors 46 and 44 are sequentially brought into operation. A humidity responsive device generally designated at 49 controls the water valve 36 to supply moisture to the air in the air conditioning unit I3 when the relative humidity of the space I6 decreases below a predetermined value.

The volume-damper 26 for the space II is operated through a link 5| by a modulating or proportioning motor 52 and in a like manner the volume damper of the space I2 is operated through a link 53 by a modulating or proportioning motor 54. The modulating motor 52 is controlled by a thermostat 55 responsive to the variations in the temperature of the air within the space I I. The temperature setting of the thermostat 55 is also adjusted by the outdoor compensator 48. In a like manner the modulating motor 54 is controlled by a thermostat 56 responsive to the variations of the temperature of the air in space I2 and this thermostat 56 is also adjusted by the compensator 48. The thermostats 55 and 56 and the motors 52 'and 54 are so arranged that when the heating coil 33 is in operation the dampers 26 and 21 are moved toward an open position upon a decrease in the temperature of the air in the spaces II and I2, and the dampers 26 and 21 are moved toward an open position when the cooling coil 39 is in operation upon an increase in temperature. The manner in which this reverse operation for summer cooling and winter heating is accomplished will be pointed out more fully hereafter.

The thermostat 41 responsive to the temperature of the space I6 controls the heating effect of the heating coil 33, the cooling effect of the cooling coil 39, the operation of the water valve 36 of the air moistening means and the reversal of the dampers 26 and 21 of the spaces I I and I2 through a step-controller generally designated at 66. The step-controller 66 includes a proportioning motor for operating a shaft 6|. The shaft 6| operates cams 62 to 68 inclusive. The came 62 and 63 operate a switch arm 69 and 1| with respect to contacts 16 and 12. The cams 64, 65,

66 and 61 operate switch arms 13, 16, 19 and 82.

with respect to contacts 14, 15, contacts 11, 18, contacts 86, 8| and contacts 83, 84 respectively. The cam 68 operates switch arm with respect to a contact 86. The shaft 6| also operates a slider 81 with respect to a potentiometer resistance element 88. The slider 81 and the resistance element 88 form a control potentiometer 89 for the proportioning motor 31 which controls the steam valve 34. As shown in Figure 1 the proportioning motor of the step-controller 6| is in one extreme position. The cams 62 to 68 are in their extreme counter-clockwise positions and the slider is in its extreme clockwise position. Assume now that the motor is operated from the extreme position shown in the drawings to the other extreme position. If this be the case the slider 81 is moved from the position shown in a counter-clockwise direction until it reaches the other end of the resistance element 88. In other words, the slider 81 is moved co-extcnsively with the movement of the motor of the step-controller Movement of the motor 66 away from the position shown first causes switch arm 69 to disengage contact 16. Upon further rotation the switch arm "II is caused to disengage contact 12. When the motor has moved half way through its complete travel, the switch arms 13, 16, 19 and.

the character H as shown in Figure 1.

82 are moved out of engagement with their respective contacts 15, 18, 8| and 84 and into engagement with their respective contacts 14, 11, 86 and 83. At the same time the switch arm 85 is moved into engagement with the contact 66.

As stated above the control potentiometer 89 controls the operation of the proportioning motor 31 which controls the supply of steam to the heating coil 33. In order that the proportioning motor 31 will not open the valve 34 during the first half of rotation of the step-controller 66 or until the slider 81 has rotated downwardly beyond the mid point of the resistance element 98, a compensator generally designated at 96 is utilized. This compensator comprises a slider 9| which may be manually moved with respect to a potentiometer resistance element 92.

Each of the control thermostats 41, 55 and 56 comprise a thermostatic element which may be of bellows type containing a volatile fluid. The thermostatic element 95 operates a slider 96 with respect to a resistance element 91 and a slider 98 with respect to a center tapped resistance element 99. The slider 96 and the resistance element 91 form a control potentiometer and the slider 98 and the resistance element 99 form what may be termed a difierential equalizer. Since all of the thermostats 41, 55 and 56 are exactly the same, like reference characters have been utilized.

Upon an increase in space temperature the slider 96 is moved to the right with respect to the resistance element 91 in the direction indicated by Upon a decrease in temperature the slider 96 is moved to the left in the direction indicated by the character C. Hereafter the right end of the control potentiometer will be designated H and the left end of the control potentiometer will be designated C.

The outdoor compensator, generally designated at 48 and which adjusts the temperature setting of the room thermostats, may comprise a bellows I66 connected by a capillary tube IN to a bulb I62 located in the fresh air duct 2|. Bulb I62 contains a volatile fluid and upon an increase in fresh air temperature the bellows I66 is expanded and upon a decrease in fresh air temperature the bellows I66 contracts. The bellows I66 operates a pivoted lever I63 which is connected to a carriage I64. The carriage I64 operates three compensating potentiometers generally designated at I65, I66 and I61 respectively. Each of these compensators comprise a slider I68 carried by the carriage I64 and a stationary resistance element I69. The upper ends of the resistance elements I69 are designated by the character H and the lower ends of the resistance elements I69 are designated by the character C. It is therefore seen that upon an increase in fresh air temperature sliders I68 are moved upwardly toward the character H and upon a decrease in fresh air temperature the sliders I68 are moved downwardly toward the character C.

The proportioning motors 31, 52, 54 and 66 may all be of the same construction and therefore like reference characters relating to the parts of each of these motors have been utilized. Therefore, each motor is provided with terminals I II and I I2 which are connected to a source of power. In other words the terminals III and II2 provide power for the operation of the proportioning motors and also provide power for the control circuits of the proportioning motors. Each proportioning motor is also provided with terminals H3, H4, II5, these terminals being suitably connected to the various control potentiometers and compensating potentiometers.

For a more thorough understanding of the construction of the proportioning motors and the manner in which they are operated by the controlling and compensating potentiometers ref erence is made to Figure 2. In describing the operation of the proportioning motors the proportioning motor 52 whichoperates the volume damper 26 of the space H is utilized and this proportioning motor is controlled by the ther-' mostat 55, the compensator 48 and the reversing switches of the step-controller" 60. In Figure 2 the proportioning motor 52 includes a relay having relay coils I20 and I2I for operating an armature I22 which is suitably connected to a switch arm I23. The switch arm I23 is adapted to engage contacts I24 and I25. When the relay coil I2I is energized more than the relay coil coil I20 the switch arm I23 is moved into engagement with the contact I25. When the relay coil I20 is energized more than the relay coil I2I the switch arm I23 is moved into engagement with the contact I24. When the relay coils I20 and I2I are equally energized theswitch arm I 23 is maintained spacedmidway between the contacts I24 and I25 as shown in Figure 2. Power is supplied to the relay by means of a stepdown transformer I26 having a secondary I21 and a primary I28 which is connected by wires I29 and I30 to the power terminals III and H2. The relay coils I20 and I2I are connected in series and across the secondary I21.

The proportioning motor 52 includes a shaft I32 which operates the link 5Iwhich in turn operates the damper 26. The shaft I32 is rc-. tated through a reduction gear train- I 33 by motor rotors I34 and I35. The rotors I34 and I35 are controlled by field, windings I36 and I31 respectively. The arrangement is such that when the field winding I31 is energized the link 5| is moved to the right to move the damper 26 of Figure 1 toward an open position and when the field winding I36 is energized the link 5| is moved to the left to move the damper 26 of Figure 1 toward a closed position. The shaft I32 I,

also operates a slider I36 with respect to a potentiometer resistance element I39. The slider I38 and the resistance lement I39 form a balancing potentiometer generally designated at I40. When the link 5| is moved toward the left, the slider I38 is moved toward the left and vice versa when the link 5| is moved toward the right the slider I38 is also moved toward the right. The shaft'l32 operates an abutment member I4I for opening limit switches I42 and I43 when the link 5I is moved to an extreme right-hand position and to an extreme left-hand position. respec tively.

The H end of the resistance element I09 of the compensator 48 and the end of the resistance element 91 of the controller 55 are connect-- ed together and to the contact 14 of the stepcontroller. In a like manner the C end of the resistance element I09 of the compensator 48 and the H end of the resistance element 91 of the controller 55 are connected together and to the contact 11 of the step-controller. The switch arms 13 and 16 of the step-controller are connected to the terminals H3 and H respectively. These terminals are connected to the left end and right end of the relay coils I20 and I2I respectively. The contact 14 of the step-controller is connected to the contact 18 and in a like manner the contact is connected to the contact 11. Switch arms 13 and 16 are adapted to engage the contacts 14 and 11 or contacts 15 and 18. As shown, during the winter time when heating is required the contacts 14 and 11 are engaged by the switch arms 13 and 16 and in the summer when cooling is required the contacts 15 and 18 are engaged by the switch arms 13 and 16. The left and right ends of the resistance element I39 of the balancing potentiometer are connected to the left and right ends respectively of the relay coils I and I2I. The slider I08 of the compensator 48, the center tap of, the resistance element 99 of the controller 55 and the slider I38 of the balancing potentiometer are all connected together and through the terminal II4 to the junction of the relay coils I20 and I2I. In series with the slider I06 is a rheostat I45 and in series with the slider I38 is a rheostat I46. The purpose of these rheostats will be pointed out more fully hereafter.

With the parts in the position shown in Figure I 2 and more particularly with the switch arms 13 and 16 engaging the contacts 14 and 11 it is seen that the left end of the relay coil I20 is connected to the left end of all of the potentiometer resistance elements, that the right end of the relay coil I2I is connected to the right ends of all of the potentiometer resistance elements and that the sliders are all connected to the junction of the relay coils I20 and I2I. By reason of these connections the compensating potentiometer, the controller potentiometer, the balancing potentiometer, and the relay coils I20 and I2I are all connected in parallel and across the secondary I21.

Omitting for the time being the operation of the rheostats I 45 and I46 and the compensator I06, upon a decrease in space temperature slider 96 is moved to the left in the direction indicated by the character C. By reason of the above referred to parallel relationship this causes partial short circuiting of the relay coil I20 to decrease the energization thereof and increases the energization of the relay coil I2I. As a result the switch arm I23 is moved into engagement with the contact I to complete a circuit from the power terminal III through wires I29 and I50, switch arm I23, contact I 25, wire I 5|, limit switch I42, wire I52, field winding I31, and wires I53 and I back to the other power terminal I I 2. Completion of this circuit energizes the field winding I31 to move the link I 5| towards the right, to move the damper 26 of Figure 1 toward an open position. Operation of the motor tomove the damper 26 toward an open position causes right-hand movement of the slider I38 of the balancing potentiometer. This righthand movement of the slider- I38 decreases the energization of the relay coil I 2| and increases the energization of the coil I20. When the slider I38 has moved sufficiently far to the right to rebalance the energization of the relay coils I20 and I2I the switch arm. I23 is moved out of engagement with the contact I25 to break the circuit through the field winding I31. In this manner upon a decrease in space temperature the damper 26 is modulated toward an open position in direct accordance with the amount of decrease in space temperature.

Upon an increase in space temperature the slider 96 of the control potentiometer is moved to the right in the direction indicated by the character H and this right-hand movement decreases the energization of the relay coil I2I and increases the energization of the relay coil I20 whereupon the switch arm I23 is moved into engagement with the contact I24. This completes a circuit from the power terminal III through wires I29 and I50, switch arm I23, contact I24, wire I54, limit switch I43, wire I55, field winding I36 and wires I53 and I 30 back to the other power terminal II2. Completion of this circuit energizes the field winding I36 to move the link 5| toward the left to move the damper 26 toward a closed position. Operation of the motor to move the damper 26 towards a closed position causes left-hand movement of the slider I38 of the balancing potentiometer. This left-hand movement decreases the energization of the relay coil I20 and increases the energization of the relay coil I2I and when the slider I38 has moved sumciently far to the left to rebalance the energizations of the relay coils I20 and I2 I the switch arm I23 is moved out of engagement with the contact I24 to break the circuit through the field winding I36. In this manner the damper 26 is modulated toward the closed position in accordance with the amount of increase in space temperature,

In a like manner movement of the slider I 08 of the compensator I06 toward the right in the direction indicated by the character C causes closing movement of the damper 26 and movement of the slider I08 to the left in the direction indicated by the character H causes opening movement of the damper 26. Therefore the mo- -tor 52 and consequently the damper 26 is controlled by the combined action of the control potentiometer 55 and the compensating potentiometer I06.

The rheostat I46 is placed in series with the slider I 38 of the balancing potentiometer to decrease the sensitivity thereof so that movement of the slider 96 of the control potentiometer through the range designated A requires complete movement of the proportioning motor 52 and therefore complete movement of the balancing potentiometer slider I38 to rebalance the relay coils I20 and I 2|. In other words, as the slider 96 of the control potentiometer is moved from the left end of the range A to the right end of the range A the damper 26 is moved from an extreme open position to an extreme closed position. By placing the rheostat I45 in series with the slider I08 of the compensating potentiometer I06 the sensitivity of the compensating potentiometer I06 is decreased and therefore the compensating potentiometer operates to shift the range or operating diiferential designated A from the left to right along the control potentiometer resistance element 91. As the outdoor temperature increases the slider I08 moves toward the left and as a result the range A or operating differential of the control potentiometer is shifted towards the right so that higher temperatures are maintained in the space. Conversely as the outside temperature decreases the slider I08 of the compensating potentiometer is moved toward the right to shift the control range A or differential of the control potentiometer toward the left to decrease the space temperature. In this manner the temperature setting of the space thermostat is adjusted in accordance with outside temperatures to raise the setting of the space thermostat as the outdoor temperature increases and to lower the setting of the space thermostat as the outdoor temperature decreases. The center tap resistance 99 engaged by the slider 98 of the controller 55 is to maintain the range A or the operating differential constant regardless of its position along the con trol potentiometer resistance element 91.

The above mode of operation is applicable for winter heating since the damper is moved toward an open position as the space temperature decreases and is moved toward a closed position as the space temperature increases. For summer cooling just the reverse action is desired and to accomplish this the switch arms 13 and 16 are moved into engagement with the contacts 15 and 10. This reverses the connections of the control potentiometer and compensating potentiometer with respect to the relay coils I20 and I2I so that upon a decrease in space temperature the damper 26 is moved toward a closed position and upon an increase in space temperature the damper 26 is moved toward an open position.

Referring now again to Figure 1 it is seen that is also seen that the control thermostat 41 and the compensator I 05 are connected to the proportioning motor of the step-controller 60 in exactly the same manner as in Figure 2 with the exception that the summer-winter change over switches are omitted. Therefore the motor of the step-controller 60 is positioned in accordance with variations in the temperature of space I0 and the temperature setting is adjusted in accordance with outdoor temperature in exactly the same manner asthe winter operation of Figure 2.

The control potentiometer 89 operated by the step-controller and the motor 31 which controls the steam valve 34 are connected in the same manner as in Figure 2 and also the manually operated compensator is connected in the same manner as the compensator of Figure 2. Since the slider 9| of the compensator is located in the righthand portion of the resistance element 92 the valve 34 will be held in a closed position until such time as the slider 81 of the control potentiometer 89 is moved to a position below the mid point of the resistance element 88. In other words the valve 34 will be maintained in a closed position until such time as the slider 81 moves below the mid point of the resistance element 88 and upon further downward movement of the slider 61 beyond this position the valve 34 will be modulated toward an open position.

Assume now the parts in the position shown in Figure 1, the outdoor temperature is relatively high and therefore sliders I08 of the compensating potentiometers are in their upper or H positions. The space temperatures are relatively high since the sliders 96 are in the righthand or H positions and as a result the dampers 26 and 21 are wide open and the motor of the step-controller 60 is in an extreme position. Line wires leading from some source of power (not shown) are designated at I59 and I60. The motor I9 which operates the fan I4 is placed in operation when the fan switch I63 is closed, this being accomplished by a circuit leading from the line wire I59 through wire I6I, fan motor I9, wire I62, fan switch I63, and wire I64 back to the other line wire I60. The fan I4 thereupon delivers conditioned air to all of the spaces l0, II and I2. The switch arm 69 of the step-controller 60 engages the contact 16 to complete a circuit from the line wire I56 through wire I66, switch arm 69, contact 18, wire I61, electric motor 42 and wire I68 back to the other line wire I60. Completion of this circuit causes operation of the compressor 40. The switch arm H of the step-controller is also in engagement with the contact 12 which completes a circuit from the line wire I59 through wire I69, switch arm 1I, contact 12, wire I10, electric motor 43 and wire I1I back to the other line wire I68. Therefore both of the compressors 40 and 4| are operated to supply the maximum amount of cooling. The switch arms 13, 16, 19 and 82 are in their lower or summer cooling positions and therefore the dampers 26 and 21 for the spaces II and I2 are operated by the space thermostats 55 and 56 for summer cooling. I

As the temperature of the space In decreases the motor 68 is operated to move the cams 62 to 68 in a counter-clockwise direction and the slider 81 in a counter-clockwise direction. After the motor has moved them through a given angle, the switch arm 69 is moved out of engagement with the contact 10 to break the circuit through the motor 42 which stops operation of the compressor 48. This decreases the amount of cooling accomplished by the cooling coil 39. Upon a further decrease in space temperature the switch arm H is moved out of engagement with the contact 12 to break the circuit through 'the motor 43 which stops operation of the compressor H. In this manner refrigeration or cooling is stopped.

Upon a further decrease in space temperature the switch arms 13, 16, 19 and 82 are moved into engagement with the contacts 15, 11, 80 and 83 respectively to reverse the action of the thermostats 55 and 56 of the spaces II and I2. At the same time the switch arm 85 is moved into engagement with the contact 86 and if the relative humidity in the space I0 is below a desired value a circuit is completed from the line wire I59 through wire I13, switch arm 85, contact 86, wire I14, humidity responsive device 49, wire I15, solenoid motor 32, wire I16, fan switch I63 and wire I64 back to the other line wire I68. Completion of this circuit energizes the solenoid motor 32 to supply moisture to the air in the air conditioning unit I3. Since the switch arm 85 and the contact 86 of the step-controller are in series with the humidistat 49 the water valve 30 cannot be opened while the refrigerating apparatus is operating. Also since the fan switch I63 is in scrieswithnthe humidistat 48 the spray 29 may not operate in case the fan is not running.

Upon a further decrease in space temperature the slider 81 of the control potentiometer 69 continues its downward movement and since at this time the slider 81, passes the mid point of the resistance element 88, the valve 34 controlling the supply of steam to the heating coil 33 is operated towards an open position which heats the air in an increasing amount as the space temperature decreases. Upon an increase in space temperature the same cycle of operation occurs except it occurs in reverse order and therefore a further description is not considered necessary.

Since the temperature and condition of the air delivered to all of the spaces is controlled by the thermostat in the space I0, and since heating and cooling load conditions in space III may differ from those in spaces II and I2, the volume dampers 26 and 21 controlling the supplete control system, upon a demand for cooling by the thermostat in the space ID the refrigeration apparatus is progressively placed in operation in accordance with the demand for cooling, and upon a demand for heating, the steam valve 34 is progressively opened in accordance with the amount of such demand. The space thermostats in the spaces II and I2 control their respective volume dampers to maintain the temperatures in the spaces at the desired value. When the space thermostat 41 in the space I0 changes from a heating cycle to a cooling cycle the controlling action of thermostats 55 and 56 in the spaces I I and I2 is reversed so that proper operation of the dampers 26 and 21 is automatically obtained. A humidity responsive device in the space I0 controls the supply of moisture added to the conditioned air and this humidity responsive device cannot operate the air moistening means in case the fan I4 is not operating or in case the refrigerating apparatus is in operation. The temperature settings of the thermostat 41 in the space I0 and of the thermostats 55 and 56 in the spaces II and I2 are adjusted in accordance with variations in outside temperature in such a manner that as the outdoor temperature increases the thermostat setting is raised. If desired the adjustment of the thermostats in accordance with outdoor temperatures may be eliminated.

Although for purposes of illustration I have shown one form of my invention, other forms thereof may become obvious to those skilled in the art upon reference to this specification and therefore this invention is to'be limited only by the scope of the appended claims and prior art.

I claim as my invention:

1. An air conditioning system for a building having a plurality of spaces, comprising in combination, means for conditioning air and delivering the conditioned air to all of said spaces, means responsive to the condition of the air in a main spacefor controlling the condition of the conditioned air delivered to all of the spaces and. to maintain the condition of the air in the main space at desired values, and means responsive to the condition of the air in the other spaces and to the condition of the air outside of the building for controlling the volume of conditioned air delivered to the other spaces to maintain the condition of the air therein at values which are varied in accordance with variations in outside conditions.

2. An air conditioning system for a building having a plurality of spaces, comprising in combination, means for conditioning air anddelivering the conditioned air to all of said spaces, means responsive to the condition of the air in amain space and to the condition of the air the air in the other spaces and to the condition or the air outside of the building for controlling the volume of conditioned air delivered to the other spaces to maintain the condition of the air therein at values which are varied in accordance with variations in outside conditions.

3. An air conditioning system for a building having a plurality of spaces, comprising in combination, means for conditioning air by changing its temperature and delivering the conditioned air to all of said spaces, thermostatic means responsive to the temperatureof the air in a main space for controlling the temperature of the conditioned air delivered to all of the spaces and to maintain the temperature of the air in the main space at desired values, and thermostatic means responsive to the temperature of the air in the other spaces and to the temperature of the air outside of the building for controlling the volume of conditioned air delivered to the other spaces to maintain the temperature of the air therein at values which are varied in accordance with variations in outside temperatures.

An air conditioning system for a building having a plurality of spaces, comprising in combination, means for conditioning air by changing its temperature and moisture content, circulating means for circulating the conditioned air to all of said spaces, thermostatic means responsive to the temperature of the air in a main space and to the temperature of the air outside of the building for controlling the temperature of the air delivered to all of the spaces and to maintain the temperature of the air in the main space at values which are varied in accordance with variations in outside temperatures, means responsive to the moisture content of the air in the main space for controlling the moisture content of the conditioned air delivered to all of the spaces and to maintain desired moisture con ditions in the main space, and means responsive to the condition of the air in the other spaces for controlling the volume of conditioned air delivered to the other of said spaces to maintain desired moisture conditions therein.

5. An air conditioning system for a building having a plurality of spaces, comprising in combination, an air conditioning unit having temperature changing means and air moistening means, circulating means for circulating air through the air conditioning unit and delivering conditioned air to all of said spaces, means responsive to the temperature and moisture content of the air in a main space and to the condition of the air outside of the building for controlling the temperature changing means and the air moistening means to control the condition of the air delivered to all of the spaces and to maintain desired temperature and moisture conditions in the main space, means responsive to the condition of the air in the other spaces for controlling the volume of conditioned air delivered to the other spaces to maintain desired conditions therein, and means for preventing operation of the air moistening means in case the circulating means is not operating.

6. An air conditioning system for a plurality temperature of the air in the main space at desired values, means responsive to the temperature of the air in the other spaces for controlling the volume of air delivered to the other spaces to maintain desired temperatures therein, and means for reversing the controlling action of the last mentioned temperature responsive means when the conditioning of the air is changed from heating to cooling and vice versa.

7. An air conditioning system for a plurality of spaces, comprising in combination, an air conditioning unit including heating means, cooling means and means for delivering conditioned air to all of the spaces, control means responsive to the temperature of the air in a main space for progressively operating the heating means and the cooling means to condition the air delivered to all of the spaces and to maintain the temperature of the air in the main space at desired values, means responsive to the temperature of the air in the other spaces for controlling the volume of air delivered to the other spaces to maintain desired temperatures therein, and means controlled by the control means for reversing the controlling action of the last mentioned temperature responsive means when the conditioning of the air is changed from heating to cooling and vice versa.

8. An air conditioning system for a building having a plurality of spaces, comprising in combination, an air conditioning unit including heating means, cooling means and means for delivering conditioned air to all of the spaces, control means responsive to the temperature of the air in a main space for operating the heating means when the temperature decreases and for operating the cooling means when the temperature increases to condition the air delivered to all of the spaces and to maintain desired temperature conditions in the main space, and means responsive to the temperature of the air in the other spaces to increase the volume of conditioned air delivered to the other spaces when the temperature therein decreases and the heating means is in operation to maintain desired temperatures therein.

9. An air conditioning system for a building having a plurality of spaces, comprising in combination, an air conditioning unit including heating means, cooling means and means for delivering conditioned air to all of the spaces, control means responsive to the temperature of the air in a main space for operating the heating means when the temperature decreases and for operating the cooling means when the temperature increases to condition the air delivered to all of the spaces and to maintain desired temperature conditions in the main space, and means responsive to the temperature of the air in the other spaces to increase the volume of conditioned air delivered to the other spaces when the temperature increases and the cooling means is in operation to maintain desired temperatures therein.

10. An air conditioning system for a building having a. plurality of spaces, comprising in combination, an air conditioning unit including heating means, cooling means and means for delivering conditioned air to all of the spaces, control means responsive to the temperature of the air in a main space for operating the heating means when the temperature decreases and for operating the cooling means when the temperature increases to condition the air delivered to all of the spaces and to maintain desired temperature conditions in the main space, and means including means controlled by the control means to increase the volume of heated conditioned air delivered to the other spaces when the temperature of the air thereof decreases and to increase the volume of cooled conditioned air to the other spaces when the temperature of the air thereof increases to maintain desired temperatures therein.

11. An air conditioning system for a building having a plurality of spaces, comprising in combination, an air conditioning unit including heating means, cooling means and means for delivering conditioned air to all of the spaces, control means responsive to the temperature of the-air in a main space for operating the heating means when the temperature decreases and for operating the cooling means when the temperature increases to condition the air delivered to all of the spaces and to maintain desired temperature conditions in the main space, means for adjusting the temperature setting of the control means in accordance with changes in temperature outside of the bui1ding,-and means responsive to the temperature of the air in the other spaces to increase the volume oi. conditioned air delivered to the other spaces when the temperature decreases and the heating means is in operation to maintain desired temperatures therein.

12. Anair conditioning system for a building having a plurality of spaces, comprising in combination, an air conditioning unit including heating means, cooling means and means for delivering conditioned air to all of the spaces, control means responsive to the temperature of the air in a main space for operating the heating means when the temperature decreases and for operating the cooling means when the temperature increases to condition the air delivered to all of the spaces and to maintain desired temperature conditions in the main space, means for adjusting the temperature setting of the control means in accordance with changes in tem-" perature outside of the building, and means including means controlled by the control means to increase the volume of heated conditioned air delivered to the other spaces when the temperature of the air thereoi. decreases and to increase the volume of cooled conditioned air to the other spaces when the temperature of the air thereof increases to maintain desired temperatures therein.

' HAROLD L. STEINFELD.

CERTIFICATE OF CORRECTION 'Patent No. 2,196, 687. I April 9, 19m.

' HAROLD L. ISTEINFELD.

it is hereby certified that error appears in the printed specification quiring correction as follows: Page 6, first and that the said rein that the same of the above numbered patent re column, line [5, claim 14., strike out the word "moisture" Letters Patent should be read with this correction the may conform to the record of the case in the Patent Office.

Signed and sealed this 25th day of June, A. D. 19m.

Henry Van Arsdale,

(Seal) Acting Commissioner of Patents.

CERTIFICATE OF CORRECTION.

'Patent No. 2,196, 687. April 9, 19m.

HAROLD L'. .STEINFELD.

It is hereby Certified that error appears in the printed specification of the above numbered patent requiring correctionas follows: Page 6, first column, line #5, .claimlp, strike out the word "moisture" d that the said Letters Patent should be read with this Correction therein that the same may conform to the record of the Case in the Patent Office.

Signed and sealed this 25th day of June, A. D. 19L 0.

Henry Van Arsdale (Seal) Acting Commissioner of Patents. 

